Method for preparing a pillared layered oxide material

ABSTRACT

There is provided a method for preparing a pillared layered material, designated MCM-36, with a characteristic X-ray diffraction pattern. Upon calcination of the swollen, non-pillared form of this material, the layers collapse and condense upon one another in a somewhat disordered fashion to form a non-swellable material. However, when the swollen layered material is intercalated with polymeric oxide pillars, the layer separation is maintained, even after calcination. A combination of tetraethylorthosilicate and zirconium alkoxide is used as a pillaring agent for treating the swollen material.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is related to copending U.S. application Ser. No.07/811,360, filed Dec. 20, 1991, which is a continuation-in-part ofcopending U.S. application Ser. No. 07/776,718, filed Oct. 15, 1991, nowabandoned, which is a continuation of U.S. application Ser. No.07/640,330, filed Jan. 11, 1991, now abandoned, the entire disclosure ofwhich is expressly incorporated herein by reference.

BACKGROUND

This application relates to a method for preparing layered materialshaving layers of polymeric oxides. The layers are spaced apart bypillars. These materials are designated MCM-36 and have characteristicX-ray diffraction patterns.

Many layered materials are known which have three-dimensional structureswhich exhibit their strongest chemical bonding in only two dimensions.In such materials, the stronger chemical bonds are formed intwo-dimensional planes and a three-dimensional solid is formed bystacking such planes on top of each other. However, the interactionsbetween the planes are weaker than the chemical bonds holding anindividual plane together. The weaker bonds generally arise frominterlayer attractions such as Van der Waals forces, electrostaticinteractions, and hydrogen bonding. In those situations where thelayered structure has electronically neutral sheets interacting witheach other solely through Van der Waals forces, a high degree oflubricity is manifested as the planes slide across each other withoutencountering the energy barriers that arise with strong interlayerbonding. Graphite is an example of such a material. The silicate layersof a number of clay materials are held together by electrostaticattraction mediated by ions located between the layers. In addition,hydrogen bonding interactions can occur directly between complementarysites on adjacent layers, or can be mediated by interlamellar bridgingmolecules.

Laminated materials such as clays may be modified to increase theirsurface area. In particular, the distance between the interlamellarlayers can be increased substantially by absorption of various swellingagents such as water, ethylene glycol, amines, ketones, etc., whichenter the interlamellar space and push the layers apart. However, theinterlamellar spaces of such layered materials tend to collapse when themolecules occupying the space are removed by, for example, exposing theclays to high temperatures. Accordingly, such layered materials havingenhanced surface area are not suited for use in chemical processesinvolving even moderately severe conditions.

The extent of interlayer separation can be estimated by using standardtechniques such as X-ray diffraction to determine the basal spacing,also known as "repeat distance" or "d-spacing". These values indicatethe distance between, for example, the uppermost margin of one layerwith the uppermost margin of its adjoining layer. If the layer thicknessis known, the interlayer spacing can be determined by subtracting thelayer thickness from the basal spacing.

Various approaches have been taken to provide layered materials ofenhanced interlayer distance having thermal stability. Most techniquesrely upon the introduction of an inorganic "pillaring" agent between thelayers of a layered material. For example, U.S. Pat. No. 4,216,188incorporated herein by reference discloses a clay which is cross-linkedwith metal hydroxide prepared from a highly dilute colloidal solutioncontaining fully separated unit layers and a cross-linking agentcomprising a colloidal metal hydroxide solution. However, this methodrequires a highly dilute forming solution of clay (less than 1 g/l) inorder to effect full layer separation prior to incorporation of thepillaring species, as well as positively charged species of crosslinking agents. U.S. Pat. No. 4,248,739, incorporated herein byreference, relates to stable pillared interlayered clay prepared fromsmectite clays reacted with cationic metal complexes of metals such asaluminum and zirconium. The resulting products exhibit high interlayerseparation and thermal stability.

U.S. Pat. No. 4,176,090, incorporated herein by reference, discloses aclay composition interlayered with polymeric cationic hydroxy metalcomplexes of metals such as aluminum, zirconium and titanium. Interlayerdistances of up to 16A are claimed although only distances restricted toabout 9A are exemplified for calcined samples. These distances areessentially unvariable and related to the specific size of the hydroxymetal complex.

Silicon-containing materials are believed to be a highly desirablespecies of intercalating agents owing to their high thermal stabilitycharacteristics. U.S. Pat. No. 4,367,163, incorporated herein byreference, describes a clay intercalated with silica by impregnating aclay substrate with a silicon-containing reactant such as an ionicsilicon complex, e.g., silicon acetylacetonate, or a neutral speciessuch as SiCl₄. The clay may be swelled prior to or during siliconimpregnation with a suitable polar solvent such as methylene chloride,acetone, benzaldehyde, tri- or tetraalkylammonium ions, ordimethylsulfoxide. This method, however, appears to provide only amonolayer of intercalated silica resulting in a product of small spacingbetween layers, about 2-3 A as determined by X-ray diffraction.

U.S. Pat. No. 4,859,648 describes layered oxide products of high thermalstability and surface area which contain interlayer polymeric oxidessuch as polymeric silica. These products are prepared by ion exchanginga layered metal oxide, such as layered titanium oxide, with organiccation, to spread the layers apart. A compound such astetraethylorthosilicate, capable of forming a polymeric oxide, isthereafter introduced between the layers. The resulting product istreated to form polymeric oxide, e.g., by hydrolysis, to produce thelayered oxide product. The resulting product may be employed as acatalyst material in the conversion of hydrocarbons.

Crystalline oxides include both naturally occurring and syntheticmaterials. Examples of such materials include porous solids known aszeolites. The structures of crystalline oxide zeolites may be describedas containing corner-sharing tetrahedra having a three-dimensionalfour-connected net with T-atoms at the vertices of the net and O-atomsnear the midpoints of the connecting lines. Further characteristics ofcertain zeolites are described in Collection of Simulated XRD PowderPatterns for Zeolites by Roland von Ballmoos, Butterworth ScientificLimited, 1984.

Synthetic zeolites are often prepared from aqueous reaction mixturescomprising sources of appropriate oxides. Organic directing agents mayalso be included in the reaction mixture for the purpose of influencingthe production of a zeolite having the desired structure. The use ofsuch directing agents is discussed in an article by Lok et al. entitled"The Role of Organic Molecules in Molecular Sieve Synthesis" appearingin Zeolites, Vol. 3, Oct., 1983, pp. 282-291.

After the components of the reaction mixture are properly mixed with oneanother, the reaction mixture is subjected to appropriatecrystallization conditions. Such conditions usually involve heating ofthe reaction mixture to an elevated temperature possibly with stirring.Room temperature aging of the reaction mixture is also desirable in someinstances.

After the crystallization of the reaction mixture is complete, thecrystalline product may be recovered from the remainder of the reactionmixture, especially the liquid contents thereof. Such recovery mayinvolve filtering the crystals and washing these crystals with water.However, in order to remove all of the undesired residue of the reactionmixture from the crystals, it is often necessary to subject the crystalsto a high temperature calcination e.g., at 500° C., possibly in thepresence of oxygen. Such a calcination treatment not only removes waterfrom the crystals, but this treatment also serves to decompose and/oroxidize the residue of the organic directing agent which may be occludedin the pores of the crystals, possibly occupying ion exchange sitestherein.

In accordance with aspects of inventive subject matter described herein,it has been discovered that a certain synthetic crystalline oxideundergoes a transformation during the synthesis thereof from anintermediate swellable layered state to a non-swellable final statehaving order in three dimensions, the layers being stacked upon oneanother in an orderly fashion. This transformation may occur during thedrying of the recovered crystals, even at moderate temperatures, e.g.,110° C. or greater. By interrupting the synthesis of these materialsprior to final calcination and intercepting these materials in theirswellable intermediate state, it is possible to interpose materials suchas swelling, pillaring or propping agents between these layers beforethe material is transformed into a non-swellable state. When theswollen, non-pillared form of these materials is calcined, thesematerials may be transformed into materials which have disorder in theaxis perpendicular to the planes of the layers, due to disorderedstacking of the layers upon one

SUMMARY

There is provided a method for preparing a pillared layered material,said method comprising the steps of:

(i) preparing a reaction mixture capable of forming a layered materialupon crystallization, said reaction mixture containing sufficientamounts of alkali or alkaline earth metal cations, a source of silicacontaining at least about 30 wt % solid silica, an oxide of aluminum,water and hexamethyleneimine;

(ii) maintaining said reaction mixture under sufficient crystallizationconditions until crystals of layered material are formed;

(iii) swelling said layered material of step (ii) by contacting saidlayered material with a suitable swelling agent; and

(iv) pillaring the swollen material of step (iii) by insertinginterspathic polymeric oxide in between the layers of said material,wherein the swollen material is contacted with tetramethylorthosilicateand zirconium alkoxide, which are hydrolyzed to form said interspathicpolymeric oxide.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an X-ray diffraction pattern of an as-synthesized form of alayered material which may be swollen and pillared.

FIG. 2 is an X-ray diffraction pattern of a swollen form of the materialhaving the X-ray diffraction pattern shown in FIG. 1.

FIG. 3 is an X-ray diffraction pattern of the pillared form of thelayered material having the X-ray diffraction pattern shown in FIG. 1.

FIG. 4 is an X-ray diffraction pattern of the calcined form of theswollen material having the X-ray diffraction pattern shown in FIG. 2.

EMBODIMENTS

The present layered oxide material may be prepared from an intermediatematerial which is crystallized in the presence of a hexamethyleneiminedirecting agent and which, if calcined, without being swollen would betransformed into a material having an X-ray diffraction pattern as shownin Table 1.

                  TABLE 1                                                         ______________________________________                                        Interplanar        Relative Intensity,                                        d-Spacing (A)      I/I.sub.o × 100                                      ______________________________________                                        30.0 ± 2.2      w-m                                                        22.1 ± 1.3      w                                                          12.36 ± 0.2     m-vs                                                       11.03 ± 0.2     m-s                                                        8.83 ± 0.14     m-vs                                                       6.86 ± 0.14     w-m                                                        6.18 ± 0.12     m-vs                                                       6.00 ± 0.10     w-m                                                        5.54 ± 0.10     w-m                                                        4.92 ± 0.09     w                                                          4.64 ± 0.08     w                                                          4.41 ± 0.08     w-m                                                        4.25 ± 0.08     w                                                          4.10 ± 0.07     w-s                                                        4.06 ± 0.07     w-s                                                        3 91 ± 0.07     m-vs                                                       3.75 ± 0.06     w-m                                                        3.56 ± 0.06     w-m                                                        3.42 ± 0.06     vs                                                         3.30 ± 0.05     w-m                                                        3.20 ± 0.05     w-m                                                        3.14 ± 0.05     w-m                                                        3.07 ± 0.05     w                                                          2.99 ± 0.05     w                                                          2.82 ± 0.05     w                                                          2.78 ± 0.05     w                                                          2.68 ± 0.05     w                                                          2.59 ± 0.05     w                                                          ______________________________________                                    

The values in this Table and like tables presented hereinafter weredetermined by standard techniques. The radiation was the K-alpha doubletof copper and a diffractometer equipped with a scintillation counter andan associated computer was used. The peak heights, I, and the positionsas a function of 2 theta, where theta is the Bragg angle, weredetermined using algorithms on the computer associated with thediffractometer. From these, the relative intensities, 100 I/I_(o), whereI_(o) is the intensity of the strongest line or peak, and d (obs.) theinterplanar spacing in Angstrom Units (A), corresponding to the recordedlines, were determined. In Tables 1-8, the relative intensities aregiven in terms of the symbols w=weak, m=medium, s=strong and vs=verystrong. In terms of intensities, these may be generally designated asfollows:

    ______________________________________                                                    w =  0-20                                                                     m =  20-40                                                                    s =  40-60                                                                    vs = 60-100                                                       ______________________________________                                    

The material having the X-ray diffraction pattern of Table 1 is known asMCM-22 and is described in U.S. Pat. No. 4,954,325, the entiredisclosure of which is incorporated herein by reference. This materialcan be prepared from a reaction mixture containing sources of alkali oralkaline earth metal (M), e.g., sodium or potassium, cation, an oxide oftrivalent element X, e.g., aluminum, an oxide of tetravalent element Y,e.g., silicon, an organic (R) directing agent, hereinafter moreparticularly described, and water, said reaction mixture having acomposition, in terms of mole ratios of oxides, within the followingranges:

    ______________________________________                                        Reactants      Useful   Preferred                                             ______________________________________                                        YO.sub.2 /X.sub.2 O.sub.3                                                                     10-80   10-60                                                 H.sub.2 O/YO.sub.2                                                                             5-100  10-50                                                 OH.sup.- /YO.sub.2                                                                           0.01-1.0 0.1-0.5                                               M/YO.sub.2     0.01-2.0 0.1-1.0                                               R/YO.sub.2     0.05-1.0 0.1-0.5                                               ______________________________________                                    

In the synthesis method for preparing the material having the X-raydiffraction pattern of Table 1, the source of YO₂ must be comprisedpredominately of solid YO₂, for example at least about 30 wt. % solidYO₂ in order to obtain the desired crystal product. Where YO₂ is silica,the use of a silica source containing at least about 30 wt. % solidsilica, e.g., Ultrasil (a precipitated, spray dried silica containingabout 90 wt. % silica) or HiSil (a precipitated hydrated SiO₂ containingabout 87 wt. % silica, about 6 wt. % free H₂ O and about 4.5 wt. % boundH₂ O of hydration and having a particle size of about 0.02 micron)favors crystal formation from the above mixture and is a distinctimprovement over the synthesis method taught in U.S. Pat. No 4,439,409.If another source of oxide of silicon e.g., Q-Brand (a sodium silicatecomprised of about 28.8 wt. % SiO₂, 8.9 wt. % Na₂ O and 62.3 wt. % H₂ O)is used, crystallization yields little or none of the crystallinematerial having the X-ray diffraction pattern of Table 1. Impurityphases of other crystal structures, e.g., ZSM-12, are prepared in thelatter circumstance. Preferably, therefore, the YO₂, e.g., silica,source contains at least about 30 wt. % solid YO₂, e.g., silica, andmore preferably at least about 40 wt. % solid YO₂, e.g., silica.

Crystallization of the crystalline material having the X-ray diffractionpattern of Table 1 can be carried out at either static or stirredconditions in a suitable reactor vessel, such as for example,polypropylene jars or teflon lined or stainless steel autoclaves. Thetotal useful range of temperatures for crystallization is from about 80°C. to about 225° C. for a time sufficient for crystallization to occurat the temperature used, e.g., from about 24 hours to about 60 days.Thereafter, the crystals are separated from the liquid and recovered.

The organic directing agent for use in synthesizing the presentcrystalline material from the above reaction mixture may behexamethyleneimine which has the following structural formula: ##STR1##Other organic directing agents which may be used include1,4-diazacycloheptane, azacyclooctane, aminocyclohexane,aminocycloheptane, aminocyclopentane,N,N,N-trimethyl-1-adamantanammonium ions, andN,N,N-trimethyl-2-adamantanammonium ions. In general, the organicdirecting agent may be selected from the group consisting ofheterocyclic imines, cycloalkyl amines and adamantane quaternaryammonium ions.

It should be realized that the reaction mixture components can besupplied by more than one source. The reaction mixture can be preparedeither batchwise or continuously. Crystal size and crystallization timeof the crystalline material will vary with the nature of the reactionmixture employed and the crystallization conditions.

Synthesis of crystals may be facilitated by the presence of at least0.01 percent, e.g., 0.10 percent or 1 percent, seed crystals (based ontotal weight) of crystalline product.

The crystalline material having the X-ray diffraction pattern of Table 1passes through an intermediate stage. The material at this intermediatestage has a different X-ray diffraction pattern than that set forth inTable 1. It has further been discovered that this intermediate materialis swellable with the use of suitable swelling agents such ascetyltrimethylammonium compounds, e.g., cetyltrimethylammoniumhydroxide. However, when this swollen intermediate material is calcined,even under mild conditions, whereby the swelling agent is removed, thematerial can no longer be swollen with such swelling agent. By way ofcontrast it is noted that various layered silicates such as magadiiteand kenyaite may be swellable with cetyltrimethylammonium compounds bothprior to and after mild calcination.

The present swollen products may have relatively high interplanardistance (d-spacing), e.g., greater than about 6 Angstrom, e.g., greaterthan about 10 Angstrom and even exceeding 30 Angstrom. These swollenmaterials may be converted into pillared materials. These pillaredmaterials, particularly silica pillared materials, may be capable ofbeing exposed to severe conditions such as those encountered incalcining, e.g., at temperatures of about 450° C. for about two or morehours, e.g., four hours, in nitrogen or air, without significantdecrease, e.g., less than about 10%, in interlayer distance.

The material having the X-ray diffraction pattern of Table 1, whenintercepted in the swellable, intermediate state, prior to finalcalcination, may have the X-ray diffraction pattern shown in Table 2.

                  TABLE 2                                                         ______________________________________                                        d (A)                  I/I.sub.o                                              ______________________________________                                        13.53 ± 0.2         m-vs                                                   12.38 ± 0.2         m-vs                                                   11.13 ± 0.2         w-s                                                    9.15 ± 0.15         w-s                                                    6.89 ± 0.15         w-m                                                    4.47 ± 0.10         w-m                                                    3.95 ± 0.08         w-vs                                                   3.56 ± 0.06         w-m                                                    3.43 ± 0.06         m-vs                                                   3.36 ± 0.05         w-s                                                    ______________________________________                                    

An X-ray diffraction pattern trace for an example of such anas-synthesized, swellable material is shown in FIG. 1. A particularexample of such an as-synthesized, swellable material is the material ofExample 1 of the aforementioned U.S. Pat. No. 4,954,325. This materialof Example 1 of U.S. Pat. No. 4,954,325 has the X-ray diffractionpattern given in the following Table 3.

                  TABLE 3                                                         ______________________________________                                        2 Theta        d (A)   I/I.sub.o × 100                                  ______________________________________                                        3.1            28.5    14                                                     3.9            22.7    <1                                                     6.53           13.53   36                                                     7.14           12.38   100                                                    7.94           11.13   34                                                     9.67           9.15    20                                                     12.85          6.89    6                                                      13.26          6.68    4                                                      14.36          6.17    2                                                      14.70          6.03    5                                                      15.85          5.59    4                                                      19.00          4.67    2                                                      19.85          4.47    22                                                     21.56          4.12    10                                                     21.94          4.05    19                                                     22.53          3.95    21                                                     23.59          3.77    13                                                     24.98          3.56    20                                                     25.98          3.43    55                                                     26.56          3.36    23                                                     29.15          3.06    4                                                      31.58          2.833   3                                                      32.34          2.768   2                                                      33.48          2.676   5                                                      34.87          2.573   1                                                      36.34          2.472   2                                                      37.18          2.418   1                                                      37.82          3.279   5                                                      ______________________________________                                    

Taking into account certain modifications, this swellable material maybe swollen and pillared by methods generally discussed in theaforementioned U.S. Pat. No. 4,859,648, the entire disclosure of whichis expressly incorporated herein be reference. The present modificationsare discussed hereinafter and include the selection of proper swellingpH and swelling agent.

Upon being swollen with a suitable swelling agent, such as acetyltrimethylammonium compound, the swollen material may have the X-raydiffraction pattern shown in Table 4.

                  TABLE 4                                                         ______________________________________                                        d (A)                  I/I.sub.o                                              ______________________________________                                        >32.2                  vs                                                     12.41 ± 0.25        w-s                                                    3.44 ± 0.07         w-s                                                    ______________________________________                                    

The X-ray diffraction pattern of this swollen material may haveadditional lines with a d(A) spacing less than the line at 12.41±0.25,but none of said additional lines have an intensity greater than theline at the d(A) spacing of 12.41±0.25 or at 3.44±0.07, whichever ismore intense. More particularly, the X-ray diffraction pattern of thisswollen material may have the lines shown in the following Table 5.

                  TABLE 5                                                         ______________________________________                                        d (A)                  I/I.sub.o                                              ______________________________________                                        >32.2                  vs                                                     12.41 ± 0.25        w-s                                                    11.04 ± 0.22        w                                                      9.28 ± 0.19         w                                                      6.92 ± 0.14         w                                                      4.48 ± 0.09         w-m                                                    3.96 ± 0.08         w-m                                                    3.57 ± 0.07         w-m                                                    3.44 ± 0.07         w-s                                                    3.35 ± 0.07         w                                                      ______________________________________                                    

Even further lines may be revealed upon better resolution of the X-raydiffraction pattern. For example, the X-ray diffraction pattern may haveadditional lines at the following d(A) spacings (intensities given inparentheses): 16.7±4.0 (w-m); 6.11±0.24 (w); 4.05±0.08 (w); and3.80±0.08 (w).

In the region with d<9 A, the pattern for the swollen material isessentially like the one given in Table 2 for the unswollen material,but with the possibility of broadening of peaks.

An X-ray diffraction pattern trace for an example of such a swollenmaterial is shown in FIG. 2. The upper profile is a 10-foldmagnification of the lower profile in FIG. 2.

Upon being pillared with a suitable polymeric oxide, such as polymericsilica, the swollen material having the X-ray diffraction pattern shownin Table 4 may be converted into a material having the X-ray diffractionpattern shown in Table 6.

                  TABLE 6                                                         ______________________________________                                        d (A)                  I/I.sub.o                                              ______________________________________                                        >32.2                  vs                                                     12.38 ± 0.25        w-m                                                    3.42 ± 0.07         w-m                                                    ______________________________________                                    

The X-ray diffraction pattern of this pillared material may haveadditional lines with a d(A) spacing less than the line at 12.38±0.25,but none of said additional lines have an intensity greater than theline at the d(A) spacing of 12.38±0.25 or 3.42±0.07, whichever is moreintense. More particularly, the X-ray diffraction pattern of thispillared material may have the lines shown in the following Table 7.

                  TABLE 7                                                         ______________________________________                                        d (A)                  I/I.sub.o                                              ______________________________________                                        >32.2                  vs                                                     12.38 ± 0.25        w-m                                                    10.94 ± 0.22        w-m                                                    9.01 ± 0.18         w                                                      6.88 ± 0.14         w                                                      6.16 ± 0.12         w-m                                                    3.93 ± 0.08         w-m                                                    3.55 ± 0.07         w                                                      3.42 ± 0.07         w-m                                                    3.33 ± 0.07         w-m                                                    ______________________________________                                    

Even further lines may be revealed upon better resolution of the X-raydiffraction pattern. For example, the X-ray diffraction pattern may haveadditional lines at the following d(A) spacings (intensities given inparentheses): 5.59±0.11 (w); 4.42±0.09 (w); 4.11±0.08 (w); 4.04±0.08(w); and 3.76±0.08 (w).

An X-ray diffraction pattern trace for an example of such a pillaredmaterial is given in FIG. 3. The upper profile is a 10-foldmagnification of the lower profile in FIG. 3.

If the material swollen with a suitable swelling agent is calcinedwithout prior pillaring another material is produced. For example, ifthe material which is swollen but not pillared is calcined in air for 6hours at 540° C., a very strong line at a d(A) spacing of greater than32.2 will no longer be observed. By way of contrast, when the swollen,pillared material is calcined in air for 6 hours at 540° C., a verystrong line at a d(A) spacing of greater than 32.2 will still beobserved, although the precise position of the line may shift.

An example of a swollen, non-pillared material, which has been calcined,has the pattern as shown in Table 8.

                  TABLE 8                                                         ______________________________________                                        2 Theta    d (A)         I/I.sub.o × 100                                ______________________________________                                        3.8        23.3          12                                                   7.02       12.59         100                                                  8.02       11.02         20                                                   9.66       9.16          14                                                   12.77      6.93          7                                                    14.34      6.18          45                                                   15.75      5.63          8                                                    18.19      4.88          3                                                    18.94      4.69          3                                                    19.92      4.46          13     broad                                         21.52      4.13          13     shoulder                                      21.94      4.05          18                                                   22.55      3.94          32                                                   23.58      3.77          16                                                   24.99      3.56          20                                                   25.94      3.43          61                                                   26.73      3.33          19                                                   31.60      2.831         3                                                    33.41      2.682         4                                                    34.62      2.591         3      broad                                         36.36      2.471         1                                                    37.81      2.379         4                                                    ______________________________________                                    

The X-ray powder pattern shown in Table 8 is similar to that shown inTable 1 except that most of the peaks in Table 8 are much broader thanthose in Table 1.

An X-ray diffraction pattern trace for an example of the calcinedmaterial corresponding to Table 8 is given in FIG. 4.

As mentioned previously, the calcined material corresponding to theX-ray diffraction pattern of Table 1 is designated MCM-22. For thepurposes of the present disclosure, the pillared material correspondingto the X-ray diffraction pattern of Table 6 is designated herein asMCM-36. The swollen material corresponding to the X-ray diffractionpattern of Table 4 is designated herein as the swollen MCM-22 precursor.The as-synthesized material corresponding to the X-ray diffractionpattern of Table 2 is referred to herein, simply, as the MCM-22precursor.

The layers of the swollen material of this disclosure may have acomposition involving the molar relationship:

    X.sub.2 O.sub.3 :(n)YO.sub.2,

wherein X is a trivalent element, such as aluminum, boron, iron and/orgallium, preferably aluminum, Y is a tetravalent element such as siliconand/or germanium, preferably silicon, and n is at least about 5, usuallyfrom about 10 to about 150, more usually from about 10 to about 60, andeven more usually from about 10 to about 40.

To the extent that the layers of the swollen MCM-22 precursor and MCM-36have negative charges, these negative charges are balanced with cations.For example, expressed in terms of moles of oxides, the layers of theswollen MCM-22 precursor and MCM-36 may have a ratio of 0.5 to 1.5 R₂O:X₂ O₃, where R is a monovalent cation or 1/m of a cation of valency m.

MCM-36 adsorbs significant amounts of commonly used test adsorbatematerials, i.e., cyclohexane, n-hexane and water. Adsorption capacitiesfor this pillared material, especially the silica pillared material, mayrange at room temperature as follows:

    ______________________________________                                        Adsorbate    Capacity, Wt. Percent                                            ______________________________________                                        n-hexane     17-40                                                            cyclohexane  17-40                                                            water        10-40                                                            ______________________________________                                    

wherein cyclohexane and n-hexane sorption are measured at 20 Torr andwater sorption is measured at 12 Torr.

The swellable material, used to form the swollen material of the presentdisclosure, may be initially treated with a swelling agent. Suchswelling agents are materials which cause the swellable layers toseparate by becoming incorporated into the interspathic region of theselayers. The swelling agents are removable by calcination, preferably inan oxidizing atmosphere, whereby the swelling agent becomes decomposedand/or oxidized.

Suitable swelling agents may comprise a source of organic cation, suchas quaternary organoammonium or organophosphonium cations, in order toeffect an exchange of interspathic cations. Organoammonium cations, suchas n-octylammonium, showed smaller swelling efficiency than, forexample, cetyltrimethylammonium. A pH range of 11 to 14, preferably 12.5to 13.5 is generally employed during treatment with the swelling agent.

The as-synthesized material is preferably not dried prior to beingswollen. This as-synthesized material may be in the form of a wet cakehaving a solids content of less than 30% by weight, e.g., 25 wt % orless.

The foregoing swelling treatment results in the formation of a layeredoxide of enhanced interlayer separation depending upon the size of theorganic cation introduced. In one embodiment, a series of organic cationexchanges can be carried out. For example, an organic cation may beexchanged with an organic cation of greater size, thus increasing theinterlayer separation in a step-wise fashion. When contact of thelayered oxide with the swelling agent is conducted in aqueous medium,water is trapped between the layers of the swollen species.

The organic-swollen species may be treated with a compound capable ofconversion, e.g., by hydrolysis, to pillars of an oxide, preferably to apolymeric oxide. In accordance with the present invention, theorganic-swollen species is contacted with tetraethylorthosilicate and azirconium alkoxide, which are both hydrolyzable compounds. Where thetreatment involves hydrolysis, this treatment may be carried out usingthe water already present in organic-swollen material. In this case, theextent of hydrolysis may be modified by varying the extent to which theorganic-swollen species is dried prior to addition of the polymericoxide precursor.

It is preferred that the organic cation deposited between the layers becapable of being removed from the pillared material without substantialdisturbance or removal of the interspathic polymeric oxide. For example,organic cations such as cetyltrimethylammonium may be removed byexposure to elevated temperatures, e.g., calcination, in nitrogen orair, or by chemical oxidation preferably after the interspathicpolymeric oxide precursor has been converted to the polymeric oxidepillars in order to form the pillared layered product.

These pillared layered products, especially when calcined, exhibit highsurface area, e.g., greater than 500 m² /g, and thermal and hydrothermalstability making them highly useful as catalysts or catalytic supports,for hydrocarbon conversion processes, for example, alkylation.

Insertion of the organic cation between the adjoining layers serves tophysically separate the layers in such a way as to make the layeredmaterial receptive to the interlayer addition of a polymeric oxideprecursor. In particular, cetyltrimethylammonium cations have been founduseful. These cations are readily incorporated within the interlayerspaces of the layered oxide serving to prop open the layers in such away as to allow incorporation of the polymeric oxide precursor. Theextent of the interlayer spacing can be controlled by the size of theorganoammonium ion employed.

Interspathic oxide pillars, which may be formed between the layers ofthe propped or swollen oxide material, may include an oxide, preferablya polymeric oxide, of zirconium or titanium or more preferably of anelement selected from Group IVB of the Periodic Table (FischerScientific Company Cat. No. 5-702-10, 1978), other than carbon, i.e.,silicon, germanium, tin and lead. Other suitable oxides include those ofGroup VA, e.g., V, Nb, and Ta, those of Group IIA, e.g., Mg or those ofGroup IIIB, e.g., B. Most preferably, the pillars include polymericsilica. In addition, the oxide pillars may include an element whichprovides catalytically active acid sites in the pillars, preferablyaluminum.

The oxide pillars are formed from a precursor material which may beintroduced between the layers of the organic "propped" species as anionic or electrically neutral compound of the desired elements, e.g.,those of Group IVB. The precursor material may be an organometalliccompound which is a liquid under ambient conditions. In particular,hydrolyzable compounds, e.g., alkoxides, of the desired elements of thepillars may be utilized as the precursors. Suitable polymeric silicaprecursor materials include tetraalkylsilicates, e.g.,tetrapropylorthosilicate, tetramethylorthosilicate and, most preferably,tetraethylorthosilicate. Suitable polymeric silica precursor materialsalso include quaternary ammonium silicates, e.g., tetramethylammoniumsilicate (i.e. TMA silicate). Where the pillars also include polymericalumina, a hydrolyzable aluminum compound can be contacted with theorganic "propped" species before, after or simultaneously with thecontacting of the propped layered oxide with the silicon compound.Preferably, the hydrolyzable aluminum compound employed is an aluminumalkoxide, e.g., aluminum isopropoxide. If the pillars are to includetitania, a hydrolyzable titanium compound such as titanium alkoxide,e.g., titanium isopropoxide, may be used.

After calcination to remove the organic propping agent, the finalpillared product may contain residual exchangeable cations. Suchresidual cations in the layered material can be ion exchanged by knownmethods with other cationic species to provide or alter the catalyticactivity of the pillared product. Suitable replacement cations includecesium, cerium, cobalt, nickel, copper, zinc, manganese, platinum,lanthanum, aluminum, ammonium, hydronium and mixtures thereof.

Particular procedures for intercalating layered materials with metaloxide pillars are described in U.S. Pat. Nos. 4,831,005; 4,831,006; and4,929,587. The entire disclosures of these patents are expresslyincorporated herein by reference. U.S. Pat. No. 4,831,005 describesplural treatments with the pillar precursor. U.S. Pat. No. 4,929,587describes the use of an inert atmosphere, such as nitrogen, to minimizethe formation of extralaminar polymeric oxide during the contact withthe pillar precursor. U.S. Pat. No. 4,831,006 describes the use ofelevated temperatures during the formation of the pillar precursor.

The resulting pillared products exhibit thermal stability attemperatures of 450° C. or even higher as well as substantial sorptioncapacities (as much as 17 to 40 wt % for C₆ hydrocarbon). The pillaredproducts may possess a basal spacing of at least about 32.2A and surfaceareas greater than 500 m² /g.

MCM-36 can optionally be used in intimate combination with ahydrogenating component such as tungsten, vanadium, molybdenum, rhenium,nickel, cobalt, chromium, manganese, or a noble metal such as platinumor palladium where a hydrogenation-dehydrogenation function is to beperformed. Such component can be exchanged into the composition,impregnated therein or intimately physically admixed therewith. Suchcomponent can be impregnated in, or on, the layered material such as,for example, by, in the case of platinum, treating the layered materialwith a solution containing a platinum metal-containing ion. Thus,suitable platinum compounds for this purpose include chloroplatinicacid, platinous chloride and various compounds containing the platinumamine complex.

The layered material may be subjected to thermal treatment, e.g., todecompose organoammonium ions. This thermal treatment is generallyperformed by heating one of these forms at a temperature of at leastabout 370° C. for at least 1 minute and generally not longer than 20hours. While subatmospheric pressure can be employed for the thermaltreatment, atmospheric pressure is preferred simply for reasons ofconvenience.

Prior to its use in catalytic processes described herein, MCM-36 ispreferably dehydrated, at least partially. This dehydration can be doneby heating the crystals to a temperature in the range of from about 200°C. to about 595° C. in an atmosphere such as air, nitrogen, etc., and atatmospheric, subatmospheric or superatmospheric pressures for betweenabout 30 minutes to about 48 hours. Dehydration can also be performed atroom temperature merely by placing the layered material in a vacuum, buta longer time is required to obtain a sufficient amount of dehydration.

The catalyst can be shaped into a wide variety of particle sizes.Generally speaking, the particles can be in the form of a powder, agranule, or a molded product such as an extrudate having a particle sizesufficient to pass through a 2 mesh (Tyler) screen and be retained on a400 mesh (Tyler) screen. In cases where the catalyst is molded, such asby extrusion, MCM-36 can be extruded before drying or partially driedand then extruded.

It may be desired to incorporate MCM-36 with another material which isresistant to the temperatures and other conditions employed in thecatalytic processes described herein. Such materials include active andinactive materials and synthetic or naturally occurring zeolites as wellas inorganic materials such as clays, silica and/or metal oxides such asalumina. The latter may be either naturally occurring or in the form ofgelatinous precipitates or gels including mixtures of silica and metaloxides. Use of a material in conjunction with MCM-36, i.e., combinedtherewith or present during its synthesis, which itself is catalyticallyactive may change the conversion and/or selectivity of the catalyst.Inactive materials suitably serve as diluents to control the amount ofconversion so that products can be obtained economically and orderlywithout employing other means for controlling the rate of reaction.These materials may be incorporated into naturally occurring clays,e.g., bentonite and kaolin, to improve the crush strength of thecatalyst under commercial operating conditions. Said materials, i.e.,clays, oxides, etc., function as binders for the catalyst. It isdesirable to provide a catalyst having good crush strength because incommercial use, it is desirable to prevent the catalyst from breakingdown into powder-like materials. These clay binders have been employednormally only for the purpose of improving the crush strength of thecatalyst.

Naturally occurring clays which can be composited with MCM-36 includethe montmorillonite and kaolin family, which families include thesubbentonites, and the kaolins commonly known as Dixie, McNamee, Georgiaand Florida clays or others in which the main mineral constituent ishalloysite, kaolinite, dickite, nacrite, or anauxite. Such clays can beused in the raw state as originally mined or initially subjected tocalcination, acid treatment or chemical modification. Binders useful forcompositing with layered materials also include inorganic oxides,notably alumina.

In addition to the foregoing materials, MCM-36 can be composited with aporous matrix material such as silica-alumina, silica-magnesia,silica-zirconia, silica-thoria, silica-beryllia, silica-titania as wellas ternary compositions such as silica-alumina-thoria,silica-alumina-zirconia, silica-alumina-magnesia andsilica-magnesia-zirconia.

The relative proportions of finely divided MCM-36 and inorganic oxidematrix vary widely, with MCM-36 content ranging from about 1 to about 90percent by weight and more usually, particularly when the composite isprepared in the form of beads, in the range of about 2 to about 80weight of the composite.

MCM-36 is useful as a catalyst component for a variety of organic, e.g.hydrocarbon, compound conversion processes. Such conversion processesinclude, as non-limiting examples, cracking hydrocarbons with reactionconditions including a temperature of from about 300° C. to about 700°C., a pressure of from about 0.1 atmosphere (bar) to about 30atmospheres and a weight hourly space velocity of from about 0.1 toabout 20; dehydrogenating hydrocarbon compounds with reaction conditionsincluding a temperature of from about 300° C. to about 700° C., apressure of from about 0.1 atmosphere to about 10 atmospheres and aweight hourly space velocity of from about 0.1 to about 20; convertingparaffins to aromatics with reaction conditions including a temperatureof from about 100° C. to about 700° C., a pressure of from about 0.1atmosphere to about 60 atmospheres, a weight hourly space velocity offrom about 0.5 to about 400 and a hydrogen/hydrocarbon mole ratio offrom about 0 to about 20; converting olefins to aromatics, e.g. benzene,toluene and xylenes, with reaction conditions including a temperature offrom about 100° C. to about 700° C., a pressure of from about 0.1atmosphere to about 60 atmospheres, a weight hourly space velocity offrom about 0.5 to about 400 and a hydrogen/hydrocarbon mole ratio offrom about 0 to about 20; converting alcohols, e.g. methanol, or ethers,e.g. dimethylether, or mixtures thereof to hydrocarbons includingaromatics with reaction conditions including a temperature of from about300° C. to about 550° C., more preferably from about 370° C. to about500° C., a pressure of from about 0.01 psi to about 2000 psi, morepreferably from about 0.1 psi to about 500 psi, and a liquid hourlyspace velocity of from about 0.5 to about 100; isomerizing xylenefeedstock components with reaction conditions including a temperature offrom about 230° C. to about 510° C., a pressure of from about 3atmospheres to about 35 atmospheres, a weight hourly space velocity offrom about 0.1 to about 200 and a hydrogen/hydrocarbon mole ratio offrom about 0 to about 100; disproportionating toluene with reactionconditions including a temperature of from about 200° C. to about 760°C., a pressure of from about atmospheric to about 60 atmospheres and aweight hourly space velocity of from about 0.08 to about 20; alkylatingisoalkanes, e.g. isobutane, with olefins, e.g. 2-butene, with reactionconditions including a temperature of from about -25° C. to about 400°C., e.g. from about 75° C. to about 200° C., a pressure of from belowatmospheric to about 5000 psig, e.g. from about atmospheric to about1000 psig, a weight hourly space velocity based on olefin of from about0.01 to about 100, e.g. from about 0.1 to about 20, and a mole ratio oftotal isoalkane to total olefin of from about 1:2 to about 100:1, e.g.from about 3:1 to about 30:1; alkylating aromatic hydrocarbons, e.g.benzene and alkylbenzenes, in the presence of an alkylating agent, e.g.olefins, formaldehyde, alkyl halides and alcohols, with reactionconditions including a temperature of from about 340° C. to about 500°C., a pressure of from about atmospheric to about 200 atmospheres, aweight hourly space velocity of from about 2 to about 2000 and anaromatic hydrocarbon/alkylating agent mole ratio of from about 1/1 toabout 20/1; transalkylating aromatic hydrocarbons in the presence ofpolyalkylaromatic hydrocarbons with reaction conditions including atemperature of from about 340° C. to about 500° C., a pressure of fromabout atmospheric to about 200 atmospheres, a weight hourly spacevelocity of from about 10 to about 1000 and an aromatichydrocarbon/polyalkylaromatic hydrocarbon mole ratio of from about 1/1to about 16/1; and reacting olefins, e.g., isobutene or isopentene, withalcohols, e.g., methanol, to produce ethers with reaction conditionsincluding a temperature of from about 20° C. to about 200° C., a totalsystem pressure of from about 1 to about 200 atmospheres, an alcohol toolefin mole ratio of from about 0.1 to about 5 and a weight hourly spacevelocity of from 0.1 to about 200; converting light olefins, e.g.,having 2 to 7 carbon atoms, to alcohol(s), ether(s) or mixtures thereofby reacting said light olefins with water under reaction conditionsincluding a temperature from about 50° C. to about 300° C., a totalpressure of at least about 5 atmospheres; and a mole ratio of water tototal olefin of from about 0.1 to about 30; and transferring hydrogenfrom paraffins to olefins with reaction conditions including atemperature from about -25° C. to about 400° C., e.g., from about 75° C.to about 200° C., a pressure from below atmospheric to about 5000 psig,e.g., from about atmospheric to about 1000 psig, a mole ratio of totalparaffin to total olefin of from about 1:2 to about 500:1, e.g., fromabout 5:1 to about 100:1; and a weight hourly space velocity based onolefin of from about 0.01 to about 100, e.g., from about 0.05 to about5.

Alpha values are reported in certain examples appearing hereinafter. Itis noted that the Alpha Value is an approximate indication of thecatalytic cracking activity of the catalyst compared to a standardcatalyst and it gives the relative rate constant (rate of normal hexaneconversion per volume of catalyst per unit time). It is based on theactivity of the highly active silica-alumina cracking catalyst taken asan Alpha of 1 (Rate Constant=0.016 sec⁻¹). The Alpha Test is describedin U.S. Pat. No. 3,354,078, in the Journal of Catalysis, Vol. 4, p. 527(1965); Vol. 6, p. 278 (1966); and Vol. 61, p. 395 (1980), eachincorporated herein by reference as to that description. Theexperimental conditions of the test preferably include a constanttemperature of 538° C. and a variable flow rate as described in detailin the Journal of Catalysis, Vol. 61, p. 395.

Various crystallites from the Examples which follow were examined bytransition electron microscopy (TEM).

EXAMPLE 1

This Example describes the synthesis of a material which may be swollenand pillared. Water, sodium hydroxide, sodium aluminate, silica(Ultrasil), and hexamethyleneimine (HMI) were combined in the followingmole ratios:

    2.5 Na.sub.2 O: Al.sub.2 O.sub.3 :30 SiO.sub.2 :10 HMI: 580 H.sub.2 O.

The reaction mixture was heated in an autoclave to 143° C. for 96 hours.The X-ray diffraction pattern for this material is shown pictorially inFIG. 1.

EXAMPLE 2

A swelling reagent was prepared by contacting a 29% solution ofcetyltrimethylammonium (N,N,N-trimethyl-1-hexadecanaminium) chloridewith a hydroxide-for-halide exchange resin (one liter of wet resin with1.4 milliequivalent/ml exchange capacity per 3 l of the solution). Itwill be referred to as 29% CTMA-OH.

A mixture of 30 g of the Example 1 wet cake (30% solids) and 150 g ofthe 29% CTMA-OH solution was reacted in the steambox for 65 hours. Theproduct was isolated by filtration, washed twice with 50 ml of water andair dried overnight yielding 10.6 g of the swollen product. The X-raydiffraction pattern for this swollen material is shown pictorially inFIG. 2. The X-ray diffraction pattern for this swollen material is alsogiven in the following Table 9.

                  TABLE 9                                                         ______________________________________                                        2 Theta   d (A)         I/I.sub.o × 100                                 ______________________________________                                        1.7       52.0          100                                                   2.8       31.6          20                                                    5.24      16.86         10                                                    5.61      15.75         6                                                     7.13      12.40         32                                                    7.99      11.06         5                                                     9.58      9.23          3                                                     12.81     6.91          3                                                     13.98     6.33          1      broad                                          14.60     6.07          2                                                     15.69     5.65          2                                                     19.60     4.53          11     broad                                          21.29     4.17          12                                                    21.92     4.05          6                                                     22.44     3.96          10                                                    23.27     3.82          6      broad shoulder                                 24.94     3.57          9                                                     25.93     3.44          26                                                    26.60     3.35          8                                                     28.00     3.19          3      broad                                          29.08     3.07          1                                                     31.51     2.839         2                                                     33.09     2.707         1      broad                                          33.75     2.656         1      broad                                          34.70     2.585         1      broad                                          36.30     2.475         1                                                     37.09     2.424         1                                                     37.74     2.384         3                                                     ______________________________________                                    

TEM analysis of crystallites confirm the separation of layers by thewelling procedure.

EXAMPLE 3

The pillaring mixture consisted of 50 g tetraethylorthosilicate (TEOs)and 50 g of Zr(n-propoxide)₄. 20 g of dry, ground swollen material asdescribed hereinbelow was added and the slurry was stirred at 80° C. for24 hours under nitrogen atmosphere. The solids were isolated byfiltration and hydrolyzed with water for 4 hours. Upon calcination amaterial with XRD pattern indicative of MCM-36 was obtained.

The swollen material, referred to hereinabove in this Example, wasobtained by reacting 330 g of the Example 1 wet cake (42% solids) and2700 ml of 29% of CTMA-OH for 48 hours in the steambox. The solid wasisolated by filtration, washed by contacting with 0.5 l of water and airdried. The X-ray diffraction pattern of this swollen material is givenin the following Table 10.

                  TABLE 10                                                        ______________________________________                                        2 Theta    d (A)         I/I.sub.o × 100                                ______________________________________                                        1.7        52.0          100                                                  2.7        32.7          28.1                                                 5.38       16.43         10.8                                                 7.12       12.41         14.5                                                 8.10       10.91         2.9                                                  9.61       9.20          1.5    broad                                         12.77      6.93          1.0                                                  14.50      6.11          0.9                                                  19.88      4.47          6.8    broad                                         21.41      4.15          6.6                                                  21.94      4.05          4.4                                                  22.46      3.96          7.7                                                  23.05      3.86          3.3    shoulder                                      23.60      3.77          3.2    shoulder                                      24.93      3.57          4.8                                                  25.93      3.44          12.4                                                 26.55      3.36          4.7    broad                                         ______________________________________                                    

What is claimed is:
 1. A method for preparing pillared layered material,designated McM-36, said method comprising the steps of:(i) preparing areaction mixture capable of forming a layered material uponcrystallization, said reaction mixture containing sufficient amounts ofalkali or alkaline earth metal cations, a source of silica containing atleast about 30 wt % solid silica, an oxide of aluminum, water andhexamethyleneimine; (ii) maintaining said reaction mixture undersufficient crystallization conditions until crystals of layered materialare formed; (iii) swelling said layered material of step (ii) bycontacting said layered material with a suitable swelling agent, and(iv) pillaring the swollen material of step (iii) by inserting silica inbetween the layers of said material, wherein the swollen material iscontacted with tetramethylorthosilicate and zirconium alkoxide, whichare hydrolyzed to form said interspathic polymeric oxide.
 2. A methodaccording to claim 1, wherein said reaction mixture has a composition interms of mole ratios within the following ranges:

    ______________________________________                                                 SiO.sub.2 /Al.sub.2 O.sub.3 =                                                           10 to 80                                                            H.sub.2 O/SiO.sub.2 =                                                                   5 to 100                                                            OH.sup.- /SiO.sub.2 =                                                                   0.01 to 1.0                                                         M/SiO.sub.2 =                                                                           0.05 to 1.0                                                         R/SiO.sub.2 =                                                                           0.05 to 1.0                                                ______________________________________                                    

wherein R represents hexamaethyleneimine and M represents alkali oralkaline earth metal.
 3. A method according to claim 2, wherein saidreaction mixture has a composition in terms of mole ratios within thefollowing ranges:

    ______________________________________                                                 SiO.sub.2 /Al.sub.2 O.sub.3 =                                                           10 to 60                                                            H.sub.2 O/SiO.sub.2 =                                                                   10 to 50                                                            OH.sup.- /SiO.sub.2 =                                                                   0.1 to 0.5                                                          M/SiO.sub.2 =                                                                           0.1 to 1.0                                                          R/SiO.sub.2 =                                                                           0.1 to 0.5.                                                ______________________________________                                    


4. A method according to claim 1, wherein said reaction mixture furthercomprises a sufficient amount of crystal formation enhancing seedcrystals.
 5. A method according to claim 1, wherein said solid silicasource is a precipitated, spray dried silica.
 6. A method according toclaim 1, wherein said swelling agent comprises an organoammonium ion. 7.A method according to claim 1, wherein said layered material of step(ii) has the X-ray diffraction pattern of Table 2, the swollen materialof step (iii) has the X-ray diffraction pattern of Table 4, saidswelling agent comprises a cetyltrimethylammonium cation, and thepillared material of step (iv) has the X-ray diffraction pattern ofTable
 6. 8. A method according to claim 1, wherein said swelling agentcomprises a cetyltrimethylammonium ion.
 9. A method according to claim1, wherein the swelling step (iii) is conducted at a pH range of 11 to14.
 10. A method according to claim 1, wherein the swelling step (iii)is conducted at a pH range of 12.5 to 13.5.
 11. A method according toclaim 1, wherein said zirconium alkoxide is zirconium tetrapropoxide.